Validate against the maximum binding index (#2892)

* Validate binding indices in create_bind_group_layout.

* Add an entry in the changelog

Author: nical

CHANGELOG.md

@@ -97,6 +97,7 @@ the same every time it is rendered, we now warn if it is missing.
 - Fix bugs when mapping/unmapping zero-sized buffers and ranges by @nical in [#2877](https://github.com/gfx-rs/wgpu/pull/2877)
 - Fix out-of-bound write in `map_buffer` with non-zero offset by @nical in [#2916](https://github.com/gfx-rs/wgpu/pull/2916)
 - Validate the number of color attachments in `create_render_pipeline` by @nical in [#2913](https://github.com/gfx-rs/wgpu/pull/2913)
+- Validate against the maximum binding index in `create_bind_group_layout` by @nical in [#2892]
 
 #### DX12
 - `DownlevelCapabilities::default()` now returns the `ANISOTROPIC_FILTERING` flag set to true so DX12 lists `ANISOTROPIC_FILTERING` as true again by @cwfitzgerald in [#2851](https://github.com/gfx-rs/wgpu/pull/2851)

wgpu-core/src/binding_model.rs

@@ -48,6 +48,8 @@ pub enum CreateBindGroupLayoutError {
     },
     #[error(transparent)]
     TooManyBindings(BindingTypeMaxCountError),
+    #[error("Binding index {binding} is greater than the maximum index {maximum}")]
+    InvalidBindingIndex { binding: u32, maximum: u32 },
 }
 
 //TODO: refactor this to move out `enum BindingError`.

wgpu-core/src/device/mod.rs

@@ -31,6 +31,9 @@ pub mod queue;
 #[cfg(any(feature = "trace", feature = "replay"))]
 pub mod trace;
 
+// Per WebGPU specification.
+pub const MAX_BINDING_INDEX: u32 = 65535;
+
 pub const SHADER_STAGE_COUNT: usize = 3;
 // Should be large enough for the largest possible texture row. This value is enough for a 16k texture with float4 format.
 pub(crate) const ZERO_BUFFER_SIZE: BufferAddress = 512 << 10;
@@ -4083,6 +4086,12 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
 
             let mut entry_map = FastHashMap::default();
             for entry in desc.entries.iter() {
+                if entry.binding > MAX_BINDING_INDEX {
+                    break 'outer binding_model::CreateBindGroupLayoutError::InvalidBindingIndex {
+                        binding: entry.binding,
+                        maximum: MAX_BINDING_INDEX,
+                    };
+                }
                 if entry_map.insert(entry.binding, *entry).is_some() {
                     break 'outer binding_model::CreateBindGroupLayoutError::ConflictBinding(
                         entry.binding,